A brake-transmission interlock system brings the vehicle transmission and the vehicle braking system into cooperation with one another through a locking device. When a driver attempts to shift the vehicle transmission from park to some other gear arrangement, the brake-transmission interlock system prevents shifting unless at least one of the vehicle brakes is engaged. Some form of locking device engages the shifting mechanism to lock the shifting mechanism if at least one of the vehicle brakes is not engaged. If at least one of the vehicle brakes is engaged, the brake-transmission interlock system controls the locking device to unlock the shifting mechanism and allow the driver to shift the vehicle transmission from park to some other gear arrangement.